The first glimpse for most viewers of Scottish actor Greg McHugh was in the opening episode of Channel 4's brilliant student comedy Fresh Meat, blow-drying Peking ducks in the living room of his student house. He was naked from the waist down – his character, geology student and part-time abattoir worker Howard Rowbottom (or is it MacCalum? He seemed to change surname in series two) having been left on his own for too long over the long summer holidays.

McHugh's bearded and bespectacled Howard observes everyday human interaction like an anthropologist trying to fathom the ways of a newly-discovered tribe of Borneo pygmies, but the actor's association with social awkwardness instantly evaporates when he invites me to meet him in his London club – that famously louche media-haunt, the Groucho.

"I've only been a member for a couple of months," he says, ordering a virgin Mary and looking perfectly at home, a jaunty handkerchief peeking out of his blazer breast pocket. His actual home is Homerton ("proper East End... proper taxi ride home from the bus stop"), where he lives with his unnamed wife ("I keep that very separate"), a "producer". Don't ask what of.

Actually, the first surprise arrived a week earlier when my phone alerted me to a new Twitter follower – you've guessed who. It felt a bit like a shot across my bows, or an impromptu piece of research, although there is not much to be gleaned from my shamefully lackadaisical Twitter output. McHugh is far more engaged, with 44,963 followers at the last count, and so up-to-date was I with his movements that I knew he had just visited his accountant. Go Greg.

Howard on walking round the house naked: 'I've just got used to wearing trousers of the mind' (Channel 4)Far more excitingly, Fresh Meat is back for a third series, and it begins with Howard approaching JP, Jack Whitehall's not-very-nice-but-dim ex-public-schoolboy, for tutelage in the art of pulling. "Are you asking me to train you up like a monkey?" asks JP in the first episode. "I like it... it would be like Driving Miss Daisy, or when Caligula made his horse into a senator."

"I've lived with a few Howards," says McHugh. "I went to uni and then drama school afterwards, and lived in quite a few student houses." Did he bring anything of himself to the role? "I would genuinely like to think that I didn't," he says. "Socially I think I'm quite comfortable, I enjoy chatting to people... but I do have my quirks. When I play Gary the Tank Commander and he's very camp and people say 'Do you bring anything of yourself?' – I'd like to say 'No', but you'd be your worst judge."

For the uninitiated – and that might mean a lot of people over the age of 30 and living south of the border – Gary: Tank Commander was a big hit in Scotland, and has a large following on YouTube and in the armed forces. It is very funny – funnier than 90 per cent of the comedy aired by BBC3, which makes it all the more surprising that BBC3 only ever showed the second (of three) series.

"I could bore you with the long political battles we had," he says, taking a fortifying sip of virgin Mary. "It was incredibly frustrating because what I found is that if you don't have someone with a vested interest in your show in England, it's going to make it more difficult. People saw it as 'the Scottish show' and they saw Burnistoun [a sketch show set in a fictional Glasgow neighbourhood] as a 'Scottish show'.

"Limmy's Show [a Scottish Bafta-winning sketch show created by Brian 'Limmy' Limond] has been supported by Matt Lucas and Graham Linehan and people like that... but [the website] British Comedy Guide said it was 'probably too niche for a mainstream audience'." Too niche or too Scottish? "Yeah... there might be that perception. With Tank Commander we tried very hard not to only make jokes that only Scottish people would understand."

Howard on culinary delights: 'It's spare meat. From the loose meat bin. Don't worry, there's some animals in that' (Channel 4)If we're considered sophisticated enough to watch subtitled shows about Danish coalition politics, surely we can cope with a few Scottish accents? Maybe it's enough to make someone vote 'yes' to Scottish independence, I suggest, but McHugh isn't biting. "I'm not heavily political," he begins cagily.

"My career was helped massively by being part of the UK and being in London, but that's on a personal level. I do get approached a lot, but I find actors who get involved in the argument often sound like they're pushing things they don't know enough about. I remember seeing Question Time with Alan Cumming and going 'Oh, no...'. I'd just rather stay out."

Does he have a prediction about the outcome? "That it will be incredibly close but I don't think Scotland will become outright independent," he says. "I think they [politicians] will work hard on the young voters. My wife's sister is 21 and her future's pretty bleak so they see an alternative as quite attractive." A Norwegian future, perhaps, happily steering its own course on a tide of oil money? "Yes, they may see a Norwegian future, but then Mr Salmond wanted an Irish future and an Icelandic future at one stage... I don't know if that was his finest hour."

McHugh's Fresh Meat character Howard may be dubbed 'the pig man of Arbroath', but the actor himself was born in the middle-class Morningside district of Edinburgh in 1980. His father was a civil servant and his mother a teacher. "No one in the arts. My brother is a professor and my other brother works with homeless people in Australia, so we're really mixed."

Obsessed with film, and certain that he wanted a future as a performer, McHugh went to university in Stirling to study, er, business. "I actually went to study sports sciences but it was too difficult," he says. "I thought it was going to be like PE. You can do business out of a textbook... it wasn't difficult at all."

Howard on 'technically' losing his virginity: 'I have my own... methods. We can get into it if you insist, but I may need some graph paper and a medical encyclopedia' (Channel 4)After getting back on track with a post-graduate course at the Royal Scottish Academy of Music and Drama in Glasgow, McHugh set off into the big, wide world of the performing arts. "I found in Scotland that people wouldn't even see me," he says, meaning agents and casting directors and the like.

"So I came to London and started running a stand-up thing in Farringdon with a friend of mine, and the girl who worked on the door, Claire Nightingale, worked for PBJ, Peter Bennett-Jones's company, and said to me one night, 'I think my agent might be quite interested in your stand-up'. And I asked, 'Oh, and who do they look after?' and she said, 'Well, Rowan Atkinson, Eddie Izzard, Harry Enfield...".

In reality his stand-up routine was "dying on its arse" – his 2005 Edinburgh show, Other People, he remembers as being voted 'worst in festival'. And then his friend, the comedian Will Andrews, suggested doing something based on the wars in Iraq and Afghanistan. "No one was touching it comedy-wise," says McHugh, who came up with the idea of a camp soldier – based on a camp man he had overheard on a bus standing up to a gang of hoodlums. "So I did a camp Edinburgh accent for him and he just laughed."

And thus was Gary the Tank Commander born, winning a Scottish Bafta for the spoof Channel 4 documentary Gary's War, before evolving into a sitcom that has roots in Bilko and Dad's Army, and was (and is) beloved by serving soldiers. "I'm doing a message for troops out there in Afghanistan for this Christmas, so it's not even faded," he says.

McHugh was even invited, in character, to a soldier's wedding. "A guy who had done seven tours of Iraq and seven tours of Afghanistan... his best man was a tank commander. I was really proud to have been asked to do that, but you end up getting photos done and the bride's looking on... it's someone else's day."

There were concerns that the show might be insulting to serving squaddies, but not a bit of it. "We only got one complaint from a forces family, not a soldier, because I soon found out that you can't offend soldiers. A soldier stopped me in Glasgow one day and said what you should be doing is a much more brutal show... the stories I could tell you..."

Howard on all-you-can -eat buffets: 'Remember, the aim here is not to have a satisfying meal out. The ultimate aim is to beat the buffet' (Channel 4)McHugh toured Scotland with a one-man stage show as Gary, and he was planning a more ambitious arena tour when "Fresh Meat happened... David Kerr, who cast me, knew Tank Commander and wanted to get me in to see what I would do with Howard."

What he has done with Howard – or what he has done in tandem with Fresh Meat creators Sam Bain and Jesse Armstrong – is to embody an object of fun who is also genuinely moving. There's a scene at the end of the first episode of the new series – in which Howard goes on a date – which is heart-breaking. "The scripts are so good that as I soon as I saw them I knew exactly how I wanted to play Howard," he says. "Post the show, some execs and producers said they didn't see Howard like that at all, but I saw him very, very clearly on the page."

Fresh Meat's ensemble cast were thrown together like genuine university freshers when the first series was filmed in Manchester in 2011, and just like first-year students, relationships were lubricated with alcohol. Now in their third year, the social aspect of filming has calmed down. "We didn't have too many crazy nights," says McHugh of filming the latest series. "There's no strong smell of booze on set in the morning.

"We did hang out a lot... I mean we're all good friends – but we were working 12-hour days and it was a heatwave as well, so we were in that tin box in Manchester [The Sharp Project – a cluster of media studios housed in a huge former Sharp electronics group warehouse]. The candles were melting on set and I'm in a jumper – so the idea of being hungover..."

Howard on fashion: 'I feel even more uncomfortable than my normal high level of discomfort. You have dressed me as Prince. I am not Prince. I am possibly the opposite of Prince' (Channel 4)Would the cast be friends naturally, or, rather like university, is there a sense of being thrown together by circumstance? "From when we started it's weird how well we got on," says McHugh. "We're incredibly different people. Jack [Whitehall] was predominantly a stand-up, Charlotte [Ritchie, who plays Oregon] hadn't done much, Zawe [Ashton, who plays Vod] was an old hand and had done loads, and Kim [Nixon] had done a lot of television as well, so we're incredibly different backgrounds but somehow these different personalities really meshed."

There is still no further news of a mooted Fresh Meat movie, an idea first aired after The Inbetweeners film cleaned up at the box-office, but there has been some interest from America in a US version of Gary: Tank Commander. "I had a really bizarre conference call with a chap in LA a couple of months ago," says McHugh, putting on an American accent. "He said, 'Oh my God, Gregory, we watch it in the office and we love it'."

Meanwhile, McHugh is writing his own sitcom for Steve Coogan's production outfit, Baby Cow. "I can't tell you too much about it," he says, before telling me all about it. "It's me playing several different characters in a leisure centre, although it's not a Brittas Empire. I'd be playing a gym attendant as well as an old woman receptionist, which every time I write it makes me laugh."

Coogan, handily enough, is one of his comedy heroes, alongside Paul Whitehouse, Ronnie Barker and Peter Sellers – an eclectic mix that suggests an original comic sensibility. Of the new series of Fresh Meat he proffers only the tantalising snippet that Howard – dumped by his humourless Dutch housemate-with-benefits Sabine – might find true love. "This time round he meets someone who is more on his spectrum," he says. And spectrum might just be the word.